hermannhkg Posted July 24, 2009 Share #1 Posted July 24, 2009 Advertisement (gone after registration) Since production ceased on the Mercury Oxide PX 625 battery, we now have to use replacements like the Lithium/alkaline LR 44/AG 13 with adapter in our MR meters and the CLs. I was wondering if there is a significant difference in performance in the meters? Are there remedies if differences do exists? Your knowhow is much appreciated! Regards, Hermann Link to post Share on other sites More sharing options...
Advertisement Posted July 24, 2009 Posted July 24, 2009 Hi hermannhkg, Take a look here Battery performance differences....... I'm sure you'll find what you were looking for!
rob_x2004 Posted July 24, 2009 Share #2 Posted July 24, 2009 My only advice is not to buy the mega expensive (silver?) batteries. They work full strength to the end and just go out like someone hits the switch. Stick with the medium/better cheapies they give you more warning. Link to post Share on other sites More sharing options...
doubice Posted July 24, 2009 Share #3 Posted July 24, 2009 The answer is not that simple…… Mercury batteries had a very flat discharge curve - they held their voltage till the end and then died suddenly. The Silver Oxide replacements have a similar discharge curve so, they would be the best alternative. The worst choice would be a PX625 Alkaline battery (PX625A) - those lose their charge gradually and one never knows at what voltage the battery actually operates. Another issue is the difference in voltage between the Mercury and Silver Oxide / Alkaline / Lithium replacements. The original Mercury based batteries were 1.35V, all the replacements are 1.5V. Unless the camera has a so-called bridge circuit (MR meters and CL’s do not) that difference will influence your readings. There are many ways to get around all of these issues - Schottky diodes installed into the meter circuits, adapters which accept the AG13/S76 1.5V batteries and have the Schottky diode already installed etc. etc. There also is a so-called Wein Cell - it has the shape of the original PX625 and uses Zinc/Air chemistry. Its voltage is 1.4V (close enough) but, the disadvantage is high cost and a short useful life. The Zinc/Air battery gets activated by removing a cover from its air vent holes - from that point on it starts draining. If you do not use the battery for a while, you can re-tape the vent holes and prolong the battery’s life. Google is your friend - just do a search with ‘PX625 Battery Replacement’ in the search window…….. Best, Jan Dvořák Link to post Share on other sites More sharing options...
hermannhkg Posted July 25, 2009 Author Share #4 Posted July 25, 2009 Thanks guys for your input, We all have to die sooner or later, so longevity of various kinds of different batteries is not a big issue. My main concern is is there variations in the meter reading with different kinds of batteries of different voltage, and how much? Thanks, Hermann Link to post Share on other sites More sharing options...
doubice Posted July 25, 2009 Share #5 Posted July 25, 2009 Thanks guys for your input, We all have to die sooner or later, so longevity of various kinds of different batteries is not a big issue. My main concern is is there variations in the meter reading with different kinds of batteries of different voltage, and how much? Thanks, Hermann Hello Hermann, Longevity of different batteries is a big issue.... As I mentioned in my post, Alkaline type batteries discharge gradually, so that you never know what the voltage of the battery actually is. It is impossible to answer, with any degree of precision, your question "is there variations in the meter reading with different kinds of batteries of different voltage, and how much?" There are simply too many variables - type of battery, its voltage, type of meter, its internal resistance rating etc etc. If in doubt, check your camera's meter against a known lightmeter - that will tell you what variations there may be between various types of batteries. If you follow the suggestions in my first post (and do some internet research yourself), you will find that the only solution is to use a propper battery, modify the camera or use an adapter. Kind regards, Jan Link to post Share on other sites More sharing options...
giordano Posted July 25, 2009 Share #6 Posted July 25, 2009 My main concern is is there variations in the meter reading with different kinds of batteries of different voltage, and how much? It's a pretty safe bet that a meter designed for PX-625 batteries relies on them delivering an effectively constant voltage. (The most likely exceptions are meters where you make the reading by zeroing the needle, e.g. the Lunasix.) The reason was to keep the circuitry simple in an age before integrated circuits and flexprints. Link to post Share on other sites More sharing options...
bobs Posted July 29, 2009 Share #7 Posted July 29, 2009 Advertisement (gone after registration) Since production ceased on the Mercury Oxide PX 625 battery, we now have to use replacements like the Lithium/alkaline LR 44/AG 13 with adapter in our MR meters and the CLs. I was wondering if there is a significant difference in performance in the meters? Are there remedies if differences do exists? Your knowhow is much appreciated! Regards, Hermann I have used a SL since 1980 and after many years failed to find correct (1.35 volt) batteries. There is a replacement battery available from America called a WeinCell MRB 625 which is 1.35 volts. It is a "AirCell" which means that it must be activated by removing the seal prior to use, it then requires at least 24 - 36 hours before it is supplying the correct voltage. From then on for the next 9 - 12 months dependent upon useage you will have correct readings on the meter. I am now back to using my SL in preference to the R4s as the viewing screen is vastly superier. Google "WeinCell Batteries" and you will find the suppliers Regards Bob Showers Link to post Share on other sites More sharing options...
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